THERMOLYSIS AND PHOTOLYSIS OF SOME SELECTED ARYL THIOESTERS

Aryl thioesters I and II were prepared and pyrolyzed in the absence of promoters either alone or in isoquinoline as solvent. Thermolysis of β-naphthyl thiobenzoate (I) on heating in air at 250°C gives benzil, benzophenone, benzoic acid, biphenyl, thio β-naphthol, 2, 2'-binaphthyl, diphenyl sulfide, thianthrene, thiophenol, phenyl β-naphthyl sulfide and 2, 2'-binaphthyl sulfide. Similar results were also obtained on heating p-tolyl thiobenzoate (II) under the same conditions in addition to thio p-cresol, p-bitolyl, p-ditolyl sulfide and phenyl p-tolyl sulfone. H2S and CO are also produced in all cases. Thermolysis of I and II in the presence of isoquinoline affords in addition to the above products, 1-phenylisoquinoline. Photolysis of I and II in acetone gives similar products to those of the thermolysis. From these results a free radical mechanism has been postulated to take place through the initial homolysis of C-S bond. No isomer redistribution proceeds the coupling reactions. © 1991, Taylor & Francis Group, LLC. All rights reserved.